Tham khảo tài liệu 'solar cells silicon wafer based technologies part 9', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Optical Insights into Enhancement of Solar Cell Performance Based on Porous Silicon Surfaces 191 Fig. 16. Current-voltage IV characteristics of Si as grown and Si of different sides Samples Rs Q Rsh kfí Vm V Im mA Voc V isc mA FF Efficiency v Si as-grown 83 PS formed on the unpolished side 78 PS formed on both sides 84 PS on both sides with lens 88 Table 2. Investigated series resistance Rs shunt resistance Rsh maximum voltage Vm maximum current Im open-circuit voltage Voc short-circuit current Isc FF and efficiency n of Si and PS where R is reflectivity. The refractive index n is an important physical parameter related to microscopic atomic interactions. Theoretically the two different approaches in viewing this subject are the refractive index related to density and the local polarizability of these entities 21 . In contrast the crystalline structure represented by a delocalized picture n is closely related to the energy band structure of the material complicated quantum mechanical analysis requirements and the obtained results. Many attempts have been made to relate 192 Solar Cells - Silicon Wafer-Based Technologies the refractive index and the energy gap Eg through simple relationships 22-27 . However these relationships of n are independent of temperature and incident photon energy. Here the various relationships between n and Eg are reviewed. Ravindra et al. 27 suggested different relationships between the band gap and the high frequency refractive index and presented a linear form of n as a function of Eg n a PEg 2 where a and p eV-1. To be inspired by the simple physics of light refraction and dispersion Herve and Vandamme 28 proposed the empirical relation as n 1 2 A I Eg B j 3 where A eV and B eV. Ghosh et al. 29 took a different approach to the problem by considering the band structure and .
